We will represent a line as a slope and y-intercept (as opposed to a pair of points), which allows us to easily check to see if the line from ( xl, yl) to ( x2, y2) is equivalent to the line from ( x3, y3) to ( x4,

y4).

floating point numbers cannot always be represented accurately in binary. We resolve this by checking if two floating point numbers are within an epsilon value of each other

It means that two lines with "equal" slopes may not be hashed to the same value. To solve this, we will round the slope down to the next epsilon and use this flooredSlope as the hash key. Then, to retrieve all lines that are potentially equal, we will search the hash table at three spots: flooredSlope, flooredSlope - epsilon, and flooredSlope + epsilon. This will ensure